condition of heightened watchfulness or preparation for action; "bombers were put on alert during the crisis"

very attentive or observant; "an alert and responsive baby is a joy"; "caught by a couple of alert cops"; "alert enough to spot the opportunity when it came"; "constantly alert and vigilant, like a sentinel on duty"

(usually followed by `to') showing acute awareness; mentally perceptive; "alert to the problems"; "alive to what is going on"; "awake to the dangers of her situation"; "was now awake to the reality of his predicament"

not unconscious; especially having become conscious; "the patient is now awake and alert"

eellike aquatic North American salamander with small forelimbs and no hind limbs; have permanent external gills

an acoustic device producing a loud often wailing sound as a signal or warning

a warning signal that is a loud wailing sound

a sea nymph (part woman and part bird) supposed to lure sailors to destruction on the rocks where the nymphs lived; "Odysseus ordered his crew to plug their ears so they would not hear the Siren's fatal song"